Hi Ryno,
Sorry Mate got off the track a bit. LOL. As I said prior the stock headers work great with the S&S taperd turbo slip ons. After that the list is endless. V&H stagerd big shots work well due to the built in crossover tube in the headers. Another one that I found that works is the Rhinhart cross back pipes. Really I need to know what style pipe you are looking at and go from there. If you are getting the bike Dyno tuned we can use many more styles of pipes due to the availability of adjustment..
Cheers Brian.